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Toxicological information

Acute Toxicity: oral

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Administrative data

Endpoint:
acute toxicity: oral
Type of information:
experimental study
Adequacy of study:
key study
Study period:
15 December 2009 - 1 April 2010
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report Date:
2010

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)
Version / remarks:
2001
Deviations:
no
GLP compliance:
yes
Test type:
acute toxic class method
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
liquid
Specific details on test material used for the study:
Fenitrothion TG (SMT, sumithion)
Brown liquid
Lot No.: 070502

Test animals

Species:
rat
Strain:
Sprague-Dawley
Sex:
female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: ORIENTBIO, Korea
- Females nulliparous and non-pregnant: yes
- Age at study initiation: 8 weeks
- Weight at study initiation: 173.3-217.8 g
- Fasting period before study: overnight (~16 hours)
- Housing: Individual
- Diet: ad libitum except prior to dosing
- Water: ad libitum
- Acclimation period: one week

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19.3-22.4
- Humidity (%): 27.8-65.1
- Air changes (per hr): 10-15
- Photoperiod (hrs dark / hrs light): 12/12

IN-LIFE DATES: From: 22 December 2009 To: 14 January 2010

Administration / exposure

Route of administration:
oral: gavage
Vehicle:
unchanged (no vehicle)
Details on oral exposure:
The test material was administered undiluted.
Doses:
300, 2000 mg/kg bw
No. of animals per sex per dose:
3 females
Control animals:
no
Details on study design:
- Duration of observation period following administration: 14 days
- Frequency of observations: 30 minutes, 1, 2, 4 and 6 hours after dosing and subsequently daily
- Frequency of weighing: Days 0, 1, 3, 7 and 14 (terminal)
- Necropsy of survivors performed: yes
Statistics:
Not required

Results and discussion

Preliminary study:
No details
Effect levels
Key result
Sex:
female
Dose descriptor:
LD50
Effect level:
> 300 - < 2 000 mg/kg bw
Based on:
test mat.
Mortality:
Two deaths occurred at 2000 mg/kg bw in the initial group of three females (Day 1 or 2). There was no mortality in either of the two groups of three females administered 300 mg/kg bw.
Clinical signs:
Clinical signs were observed in all rats at 2000 mg/kg bw and included reduced activity, lacrimation, salivation, tremor, chromaturia and perineal staining. All signs had resolved by Day 9. Signs at 300 mg/kg bw included perineal soiling, lacrimation, salivation and tremor. Signs resolved by Day 5.
Body weight:
Transient slight reductions in bodyweight were seen in surviving animals of both dose groups.
Gross pathology:
There were no treatment-related findings at necropsy.

Any other information on results incl. tables

Summary of mortality

Group

Dose level (mg/kg bw)

Number of rats

Mortality

1

2000

3F

2/3

2

300

3F

0/3

3

300

3F

0/3

Applicant's summary and conclusion

Interpretation of results:
Category 4 based on GHS criteria
Conclusions:
The acute oral LD50 of fenitrothion was found to be >300 -<2000 mg/kg bw;= fenitrothion therefore meets the criteria for classification for acute oral toxicity in Category 4 according to the CLP Regulation.
Executive summary:

The acute oral toxicity of fenitrothion was investigated in an Acute Toxic Class study according to OECD 423. Three females were initally administered a dose of 2000 mg/kg bw and observed for 14 days.  Due to mortality in this group, two additional groups of three females were administered 300 mg/kg bw in sequence, according to the study guideline. Two deaths occurred at 2000 mg/kg bw in the initial group of three females (Day 1 or 2).  There was no mortality in either of the two groups of three females administered 300 mg/kg bw. Clinical signs were observed in all rats at 2000 mg/kg bw and included reduced activity, lacrimation, salivation, tremor, chromaturia and perineal staining; all signs had resolved by Day 9.  Signs at 300 mg/kg bw included perineal soiling, lacrimation, salivation and tremor; all signs had resolved by Day 5. Transient slight reductions in bodyweight were seen in surviving animals of both dose groups. There were no treatment-related findings at necropsy. The acute oral LD50 of fenitrothion was found to be >300 -<2000 mg/kg bw; fenitrothion therefore meets the criteria for classification for acute oral toxicity in Category 4 according to the CLP Regulation.